Light-dissolver



H. M. EWING.

LIGHT nlssoLvER.

FILED JUNE 11', 191e.

APPLICATION Patented Deo. 27, 1921.

UNITED STATES PATENT OFFICE.

HOWARD 1I. EWING, OF LOS ANGELES, `CALIFORNIA, ASSIGN OR TO FAMOUS PLAYERS- LASKY CORPORATION, A CORPORATION OF NEW YORK.

LIGHT-DISSOLVER.

Specification of Letters Patent.

Patented Dec. 27, 1921.

Application led June 17, 1918. Serial No. 240,386.

the following is a s ecitication.

This invention re ates to illuminating ap paratus, more particularly adapted to motion picture illumination; and it is an object of this invention t'o provide a device which will cause a perfectl lgadual dimming or dissolving of the lig t, and, conversely,

cause a perfectly gradual brightening of the li ht, under accurate and complete control o the operator. It is afurther object to provide such a device in simple, inexpensive and easily operated form. The device is here shown in form adapted to illumination of scenes etc. for photographic work.

The fundamentals of my invention will be readily understood from the following detailed description of a preferred and specific embodiment of the invention. In this description and in the accompanying drawings I show and describe a form of device having several preferred features; but it will be understood that the invention is not limited to the specific details herein set forth, these details being described for the purpose of clearly describing the whole invention and not for the purpose of limitation.

In the accompanying drawings Figure 1 is a small side elevation of a lamp equipped with my improved device; Fig. 2 is an en larged front elevation of the same; Fig. 3 is a section taken on line 3--3 of Fig. 2; Fig. 4 is a partial plan of the device, the view being taken as indicated by line 4-4 on Fig. 2; Fig. 5 is an enlarged sectional detail taken as indicated by line 5 on Fig. 4; and Fig. 6 is a small view showing the light dissolving curtain itself. g

I show my invention applied to two double arc lamps, each of which is contained within a casin 10. Each of these arc lamps has a double ight. In practice, there is a central carbon 11 and two lateral carbone 12; so that in each lamp there are two horizontally spaced oints of illumination as indicated at 1. hese points of illumination are spaced apart horizontally (or, more generally speakin transversely of the line of movement of tghe dissolve curtain) and the two sets of points of illumination are spaced apart vertically, or longitudinally of the movement of the dissolve curtain. Now,

Aalthough my dissolve curtain operates etiiciently when applied even to a single lamp having a single point of illumination, it gives most efficient results when applied to such a lamp arrangement as herein illustrated, with one or more sets of spaced points of illumination. The specific con struction of the lamps is of course immaterial to the present invention.

The two lamp casings 10 may be supported in any suitable manner, as upon a supporting standard 15. I provide a removable casing 16, which is in the form of a frame adapted to be removably placed upon the lamp casing 10. This frame casing 16 has a rear frame 17 made to fit around the forward ends of the lamp casings. Extending forwardly of the frame 17 there is a sort of frame boxing, preferably made of sheet metal, and having sides 2O and top and bottom` 21, and having at its front an openingv which is surrounded by top and bottom anges 22 and side fianges 23. The dissolve curtain 24 covers the opening, and the edges of the dissolve curtain lie behind these flanges at opposite edges of the opening. At the top and bottom of the frame casing there is a boX 25 (see Fig. 3); in which boxes are housed the two rollers 27 upon and between which the curtain 24 is carried. These two rollers are provided with crank handles, or with any other suitable means for causing their rotation, whereby either of the rollers may be rotated to draw the curtain 24 either up or down.

The curtain 24 is made of any suitable materi al and has one end portion 3() relatively transparent and the other end portion 31 relatively opaque. In actual practice, and in a preferred form of the device, I make this curtain of a suitable fabric, and preferably of thin silk; and the portion 30 is made of white silk, or silk of some light color, so that it is relatively highly transparent or translucent; and the portion 31 I make preferably of black or some dark colcred silk, so that this portion 31 is relatively opaque. (It is not necessarily absolutely opaque. It may be only relatively so; or it may be opaque, or relatively opa ue, to actinic rays by bein suitably co ored). The preferred metho of joining the two will be noted that the portions of the curtain is shown in the drawing. There is a V-shaped line of juncture at 32, central and longitudinal oit the curtain, and thus one ot' the curtain portions projects a V-shaped end into the other curtain portion. In practice I prefer to have the relatively opaque portion 31 project a V-shaped end into the relatively transparent or translucent portion 30.

ln order to make the dissolving device easily applicable to and removable from the lamp casings, I provide the frame casing 16 with a pair of hooks or other suitable ineinbers as shown at 35; and these members 35 hook into two et' the ventilation openings 36 in the upper part of the upper lamp casing l0. In the bottom part of casing 16 I provide a transverse angle bar 37 which bears back against the lower edge of the lower casing 10. The casing 16 may thus be easily removed 'rcm the lamp casing by moving the lower end ot' casing 16 outwardly and then lifting it. j

lVhen the curtain is wound upon the lower roller 27, then the framed opening will be entirely curtained by the translucent portion 30 of the curtain; and the highest illumination will be obtained. (This is true for the arrangement shown herein; the opposite is true if the dark end of the curtain be uppermost, and either arrangement may be used at will). This illumination, although it is very high and very efficient, is also most perfectly diitused; so that very little or no shadow is cast. This diffusion is due to the translucency and diffusive quality of the material of the curtain. If it is now desired to gradually cut down the illumination, the curtain is wound upwardly (or it would be downwardly if the curtain were reversed end for end) and as the curtain moves upwardly, the upper point 32 of the opaque portion 31 moves up between the points of illumination. As the opaque portion moves upwardly, the amount of illumination is gradually cut down, until, when the curtain opening is entirely covered by the opaque portion, the illumination is cut down to a minimum, or to none. During the dissolving action, as the opaque portion of the curtain is moved upwardly, it point of the opaque portion moves first between the two lower points of illumination and then by its gradual spreading` action gradually covers those points of illumination; the point of the opaque portion then moving upwardly between the two upper points of illumination and then by the gradual spreading of the opaque portion, these two upper illuminations are covered. This action, which gradually covers the points of illumination, rather than suddenly covering a single point of illumination, or suddenly and simultaneously covering all of the several points of illumination at ence, conduces substantially to the gradual dissolving ol the light; cutting oill gradually what little light tnerc is which is direct rather than dil'lused and obviating any possibility ot an apparent line of shadow moving over the illuminated scene. However, it will be noted that almost all of the transmitted light is diffused by the translucent part of the curtain; so that the major action of dissolving the light is due to the perfectly gradual substitution et the relatively opaque part ot` the curtain or the relatively t'ansparent or translucent part ol' the curtain.

l have now described a, specilic :lorm of; my invention in some detail and particularity; but this description is given for the purpose of making my invention most easily intelligible rather than for the purpose et limiting the invention to the specilic details herein set forth. I believe my invention to be broad and fundamental rather than limited and specilic; and the following claims are accordingly directed broadly as well as speciiically to the device herein set forth and described.

Having described a preferred torni et invention, I claim:

1. A light dissolve screen comprising a continuous curtain embodying a l'abric one end part et which is translucent and light dispersive and the other end part oli which is relatively opaque, the two parts joining each other on a V-shaped line.

2. A light dissolve screen comprising` a continuous curtain embodying a thin labric one end part of which is light in color and light dispersive and the other dark in color and the dark part extending a V-shaped portion into the light part.

In a device of the character described, an open front casing and a. lamp therein, rollers at opposite edges of the liront of the casing, and a continuous curtain on the rollers movable longitudinally therebetween, said curtain having an end part which is translucent and light dispersive and au opposite end part relatively opaque and the opaque part projecting into and joining the translucent part on a V-shapcd lknmation.

4. In a device of the character described, an open front casing` and a lamp therein. a frame casing removably mounted on the lamp casing, rollers at top and bottom ol said frame easing, and a curtain movable between the rollers, said curtain having a translucent end portion and a relatively opaque end portion, the two portions joiningeach other on a V-shaped line of juncture, said V being central and longitudinal ol the curtain.

5. In combination with a lamp having two spaced points oi illumination, a dissolve eurtain adapted to be moved betere the lamp transversely to the line ol spacing of the points of illumination, said curtain havin a relatively transparent ortion and a re atively opa ue portion, tllie two portions joining each ot er along a central and longitudinal V-shaped line.

6. In combination with a lamp having a plurality of sets each of two transversely spaced points of illumination, the sets being longitu inally spaced, a dissolve curtain ada ted to be moved before the lamp longitudinally, said curtain having a relatively transparent portion and a relatively opaque portion, the two portions 'oning each other along a central and longitudinal V-shaped line.

7. A light dissolving screen embodying a continuous sheet of material one end part of which is translucent and adapted to diffuse light in passing through it and the otherend of which is relatively opaque, the

two end parts joining each other on a V- shaped line of juncture, the axis of the V being longitudinal of the screen.

8. A light dissolving screen embod ing a continuous curtain one end part of w ich is translucent and dispersive of light and the otherend part relatively opaque, the two parts joining each other on a line diagonal across the curtain.

9. A light dissolving screen embodying a r,

continuous curtain of a thin fabric one end part of which is translucent and dispersive of light and the other end part relatively opaque, the two parts joining each other on a line diagonal across the curtain.

In witness that I claim the foregoing I have hereunto subscribed my name this 11th day of June, 1918.

HOWARD M. EWING. 

